Method of forming teeth on combs for sheep shear hand-pieces



April 30, 1957 c. H. SPENCER 7 2,790,283

umaon 0F FORMING TEETH ON COMBS FOR SHEEP SHEAR HAND-PIECES Filed Feb. 2, 1956 United States Patent '0 METHOD OF FORMENG TEETH ON COMBS FOR SHEEP SHEAR HAND-PECES Charles Haddon Spencer, Dursley, England, assignor to R. A. Lister & Company Limited, Dursley, England Application February 2, 1956, Serial No. 563,142

Claims priority, application Great Britain February 22, 1955 7 Claims. (Cl. 51--285) This invention relates to a method of forming teeth of a comb for a hand-piece of a machine for shearing hair, wool or other filamentous formations (e. g., a sheep shearing machine or a horse clipping machine), and has particular reference to the grinding of wedge-shaped teeth separated by gullets.

By wedge-shaped is meant teeth which taper from their roots to their tips, and also taper from one face to the opposite face of the comb. Thus, the teeth are always formed with a fiat surface on one face (i. e., the cutting face), and the section of each tooth, normal to that face, considered at various stations along the length of the tooth, consists of a series of similar triangles proportionately increasing in size from tip to root. In plan the cutting face of each tooth tapers to a thin almost sharp edge at its tip.

Because of the very fine taper at the tips of the comb teeth a crushing roller, for forming a grinding wheel to grind the comb teeth, would necessarily have sharply tapered crushing discs which would not stand up to the strain of forming the grinding wheel.

It is an object of the invention to provide an improved method of grinding such teeth.

This ditficulty is avoided according to the present invention by first simultaneously grinding, with a ribbed grinding wheel associated with a crushing roller, a series of equally non-adjacent gullets to form the adjacent one sides of the teeth which flank them, and then simultaneously grinding, with a second ribbed grinding wheel associated with a second crushing roller, another series of identically equally non-adjacent gullets spaced from the first series, and so on, as necessary, until both sides of all of the teeth have been ground. It is desirable to use separate grinding wheels, in the same or dilferent machines, for each operation. In the case where the grinding is done in two operations on, say, a ten-toothed comb, gullets numbers 1, 3, 5, 7 and 9 would be ground in the first operation, and gullets numbers 2, 4, 6 and 8 in the second operation.

By using this method, the grinding surfaces of each grinding wheel are spaced apart to such an extent that a crushing roller adapted to form such a grinding wheel does not require sharply tapered crushing discs.

According to a further feature, the comb, when to have Wedge-shaped teeth as above defined, is laid over at such an angle to the traverse of the grinding Wheel during grinding that, by using a predetermined profile on each grinding wheel, and by grinding with straight travel generally along the length of the comb (i. e., from front to back, or vice versa), the desired wedge-shaped teeth are produced.

The accompanying drawings illustrate the method of the invention applied to the grinding, in two operations, of a sheep shear comb having ten wedge-shaped teeth. In these drawings:

Figure l is an elevation of a first crushing roller which is used for forming or dressing a first grinding wheel to perform the first operation;

2,790,283 Patented Apr. 30, 1957 Figure 2 is a plan view of the comb after the first operation;

Figure 3 is similar to Figure 1 but shows a second crushing roller for forming or dressing a second grinding wheel to perform the second operation;

Figure 4 is a plan view of the comb after the second operation; and

Figure 5 is an edge view of the comb showing how it is laid over during both operations.

The two grinding wheels are omitted from the drawings, but their shape and position will be obvious to those skilled in the art. The roller of Figure l is fashioned with lands or discs 11 for forming, or dressing, grinding ribs on the first grinding wheel, which grinds alternate gullets so as to form the adjacent sides of the flanking teeth as shown at 12 in Figure 2, leaving the sides of the teeth which flank the intermediate gullets untouched, and flat, as indicated at 13.

During this first grinding operation the comb, in the example given, is held at 33 to the line of traverse of the grinding wheel as shown in Figure 5, the said line of traverse being indicated by the arrow 14.

Next, the intermediate gullets are operated on by a second grinding wheel which is formed, or dressed, by the lands or discs 15 of the crushing roller of Figure 3. This grinding wheel forms the tooth sides which are adjacent the-intermediate gullets as shown at 16, the comb being again held as shown in Figure 5.

By forming the teeth in two operations in this way it is possible for the lands or discs 11, 15 to be robust, whereas if the teeth were formed in one operation the lands or discs of the single crushing roller to be used would have a very slender form similar to the teeth themselves.

The two grinding operations can conveniently be carried out in two different grinding machines, although both could be done in one machine if the crushing rollers and grinding wheels for the two operations are set up in turn.

When a different machine is used for the second grinding operation, the system of transfer jigging is used to facilitate accurate grinding, the jig with a row of, say, thirty partly-formed combs on it, all being laid over at the appropriate angle, being transferred bodily from one machine to the other and accurately located in its new position in the second machine.

In the first grinding machine the grinding wheel is rotated at a suitable cutting speed and reciprocated longitudinally along the row of combs, together with a suitable vertical down feed, so as to form by grinding the first set of gullets; while after the row of combs, in its jig, has been transferred to the second machine and accurately set up, the second grinding wheel is reciprocated, in a similar manner to the first, longitudinally along the row of combs so as to form by grinding the second set of gullets.

Because the combs are laid over at a predetermined a ngle, and a predetermined profile is formed on each grinding wheel, the desired wedge-shaped 'teeth are produced by the-two successive operations.

The method can be used for grinding teeth on wide or narrow combs, and can be used equally well for combs having an even number of teeth (and therefore an odd number of gullets between the teeth), and for a comb having an odd number of teeth (and therefore an even number of gullets between the teeth). Moreover, the teeth of the combs could be formed in more than two operations (e. g., three or four operations) with crushing rollers and grinding wheels having appropriately spaced lands or discs, and grinding ribs respectively.

If desired, a slave and master crushing roller can be included at opposite ends of the bed of each machine;

the master roller, of correct profile, can be used to 3 form a grinding surface of the grinding wheel when it has worn beyond acceptable limits. After reforming, and before further grinding of combs, the slave crushing roller is ground to correct form by means of the newly dressed Wheel and thereby becomes'the new master. The master and slave rollers thereby alternate their functions.

Alternatively, the grinding wheel can be dressed to the required shape by other means, for example by diamond dressing, the diamond being mounted in equipment of the pantograph type and controlled from a suitable master profile.

What I claim as my invention and desire to secure by Letters Patent of the United States is:

1. The method of forming teeth of a comb for a hand-piece of an animal-shearing machine which includes simultaneously grinding, with a ribbed grinding wheel of which the ribs are dressed by a crushing roller on a parallel axis, a series of equally non-adjacent gullets to fiorm the adjacent one sides of the teeth which flank them, and then simultaneously grinding, with a second ribbed grinding wheel of which the ribs are dressed by a second crushing roller, having its axis parallel to that of the second grinding wheel, another series of identically equally non-adjacent gulljets spaced from the first series, and so on, as necessary, until both sides of all of the teeth have been ground, the grinding wheels being axially located relatively to the comb.

2. The method forming wedge-shaped teeth of a comb for a hand-piece of an animal-shearing machine which includes simultaneously grinding, with a ribbed grinding wheel of which the ribs are dressed by a crushing roller on a parallel axis, a series of equally non-adjacent gullets to form the adjacent one sides of the teeth which flank them, and then simultaneously grinding, with 'a second ribbed grinding wheel of which the ribs are dressed by a second crushing roller, having its axis parallel to that of the second grinding wheel, another series of identically equally non-adjacent gullets spaced from the first series, and so on, as necessary, until both sides of all of the teeth have been ground, the grinding wheels being axially located relatively to the comb, and the comb being supported with its plane parallel to the axis of each grinding wheel but at an angle to the traverse thereof for enabling the grinding wheel ribs to apply the wedge-shaped form to the comb teeth.

3. The method of forming teeth of a comb fora handpiece of an animal-shearing machine which includes simultaneously grinding, in one machine and with a ribbed grinding wheel of which the ribs are dressed by a crushing roller on a parallel axis, a series of equally nonadjacent gullets to form the adjacent one sides of the teeth which flank them, and then simultaneously grinding, in a second machine and with a second ribbed grinding wheel of which the ribs are dressed by'a second crushing roller, having its axis parallel to that of the second grinding wheel, another series of identically equally nonadj acent gullets spaced from the first series, and so on, as necessary, until both sides of all of the teeth have been ground, the grinding wheels being axially located relatively to the comb.

4. The method of forming teeth of a comb for a handpiece of an animal-shearing machine which includes setting up a. plurality of the combs in a row in a transfer jig, securing the jig in a grinding machine and simultaneously grinding, with a ribbed grinding wheel, of which the ribs are dressed by a crushing roller on a parallel axis, a series of equally non-adjacent gullets in each comb to form the adjacent one sides of the teeth which flank them, transferring the jig with the combs in position to a second grinding machine and then simultaneously grinding, with a second ribbed grinding wheel of which the ribs are dressed by a second crushing roller, having its axis parallel to that of the second grinding wheel, another series of identically equally non adjacent' gullets in each comb spaced from the first series, and so on, as necessary, until both sides of all of the teeth have been ground, the grinding wheels being axially located relatively to the comb.

5. The method of forming teeth of a comb for a handpiece of Ian animal-shearing machine which includes simultaneously grinding, with a ribbed grinding wheel of which the ribs are dressed by a crushing roller on a parallel axis, alternate gullets to form the adjacent one sides of the teeth which flank them, and then simultaneously grinding, with a second ribbed grinding wheel of which the ribs are dressed by a second crushing roller, having its axis parallel to that of the second grinding wheel, the intermediate gullets so as to form theother sides of the teeth.

6. The method of forming wedge-shaped teeth of a comb for a hand-piece of an animal-shearing machine which includes simultaneously grinding, in one machine and with a ribbed grinding Wheel of which the ribs are dressed by a crushing roller on a parallel axis, alternate gullets to form the adjacent one sides of the teeth which flank them, and then simultaneously grinding, in a second machine and with a second ribbed grinding wheel of which the ribs are dressed by a second crushing roller, having its axis parallel to that of the second grinding wheel, the intermediate g-ullets so as to form the other sides of the teeth, the comb being supported relatively to each grinding wheel at an angle to the traverse thereof for enabling the grinding wheel ribs to apply the wedgeshaped form to the comb teeth.

7. The method according to claim 6 in which a plurality of the combs are set up in a row in a transfer jig which is secured to each grinding machine in turn.

References fiited in the file of this patent UNITED STATES PATENTS 261,650 Ashworth July 25, 1882 768,790 Durham -2 Aug. 30, 1904 948,953 Chandler Feb. 8, 1910 1,259,077 Burns Mar. 12, 1918 1,296,317 Rice Mar. 4, 1919 1,513,758 Hanson Nov. 4, 1924 1,640,991 Hanson Aug. 30, 1927 1,702,160 Hanson Feb. 12, 1929 1,894,067 Smith Jan. 10, 1933 2,536,864 Strickland et al. Jan. 2, 1951 FOREIGN PATENTS 715,688 France Dec. 7, 1931 

